The present invention relates to a flightless rock auger suspended from a derrick and powered by a shaft linked to a power source for removing plugs of rocks from post holes.
Poles for power lines and communication purposes are required to be vertical and arrange din straight lines. The poles may be planted in positions which are relatively inaccessible. A crane may be utilized for providing an outreaching means. Typically a digger derrick consists of a telescopic mobile crane from which is suspended a torque head. A flighted auger is suspended from the torque head and utilized for drilling in soil containing loose rock. The digger derrick is advantageous for extending the auger to the desired location. The auger may be stowed in a fixed position or extended in a telescoping position as needed to reach the desired location for drilling the hole.
Depending on the nature of the digging device, its digging element, or auger, torque head or hydraulic pressure is typically exerted on the digging element via air or oil hydraulic pressure exerted by the crane or cylinder in cooperative engagement therewith for forcing the digging element into the earth.
Although the conventional flighted auger is adequate for drilling through soil, or even soil with loose rock, the drilling operation must be suspended upon hitting a large rock or rock ledge because the flighted auger cannot penetrate the hard rock surface. The flighted auger is then lifted out of the hole and conventional methods of removing the obstruction with a steel shaft, crowbar, or explosive charge are used to break-up the hard rock. The flighted auger is then lowered into the hole to remove the loose rock.
A considerable amount of time is lost during the rock break-up and removal procedure. Moreover, an effort is continually being made to minimize work with explosives due to the liability of injury to workers and/or damage to residents or businesses in the area which may be in the area of the blasting zone and susceptible to rock or vibration damage.